The Shaido War was a military campaign begun in 999 NE when the Shaido clan of the Aiel rejected the proclamation of Rand al'Thor as the Car'a'carn or chief of chiefs of the Aiel people at Alcair Dal. Couladin, claiming the leadership of the clan although he had never been to Rhuidean, led the entire Shaido clan, some 160,000 people, into Cairhien on a campaign of conquest and destruction.
Al'Thor, commanding seven clans at that time, led his forces into Cairhien in pursuit, culminating in the Second Battle of Cairhien, where Couladin was killed by Mat Cauthon and the Shaido were put to rout, eventually regrouping in Kinslayer's Dagger under the leadership of the clan's Wise Ones and Couladin's lover Sevanna. Sevanna brokered deals with both the White Tower faction of the Aes Sedai and a mysterious man and woman (later revealed to be the Forsaken Sammael and Graendal) to ensure the capture of al'Thor. Sevanna double-crossed the Tower Aes Sedai at the Battle of Dumai's Wells, where 40,000 Shaido and 400 Wise Ones surrounded the Aes Sedai, their escort and the captured Rand al'Thor. During the battle both sides were taken by surprise when Lord Perrin Aybara led a mixed force of Aiel, Cairhienin, Tairens, Mayeners, Two Rivers bowmen, and Salidar Aes Sedai in attacking them. As the battle reached a crescendo, al'Thor was freed and the Asha'man arrived in force. Thousands of Shaido were slaughtered in the ensuing massacre and put to flight.
The Shaido again regrouped in the mountains, and Sevanna distributed "traveling boxes" given to her by Sammael that would carry the Shaido to new and fresh lands to conquer. Instead, the Shaido were scattered in groups across the south and west of the continent, their unexpected arrival sowing chaos in those lands. Sevanna and all 400 of the Shaido Wise Ones traveled as one group, however, and upon their arrival in Altara they set about regrouping as many forces as possible. Within a few months they had secured a new base of operations at the city of Malden and had managed to gather in most, if not all, of the Shaido forces that had been scattered.
The Shaido's presence in Malden had been noted by the invading Seanchan, and, in alliance with forces under Perrin Aybara, Banner-General Tylee Khirgan destroyed the Shaido forces for good at the Battle of Malden. Most of the channeling Wise Ones were taken as damane by the Seanchan after the battle.
In the aftermath of the disaster, the Wise One Therava assumed command of what was left of the clan, made Galina her slave, and ordered the Shaido to return home over the Spine of the World and never leave the Waste again, thus ending the Shaido War.